Cummins Inc. presented the new QSX11.9 and QSX15 heavy-duty engine duo to the off-highway industry at Bauma
Featuring the performance-enhancing technology of Cummins Xtra-High Pressure Injection (XPI) fuel system and a variable geometry turbocharger, the QSX engines represent a major leap forward in high-power productivity for construction, agricultural and mining equipment across the 300- to 600-hp (224-447 kW) range, the company asserts.
The 11.9-liter and 15-liter QSX are supplied as fully integrated air-intake-to-exhaust aftertreatment systems to meet 2011 EPA Tier 4 Interim and EU Stage IIIB regulations. The engines use a Cummins Particulate Filter to reduce Particulate Matter (PM) emissions by over 90 percent and incorporate a proven cooled Exhaust Gas Recirculation (EGR) system to reduce oxides of nitrogen (NOx) emissions by 45 percent.
While achieving low emissions, the QSX engines will lower operating costs with up to 5 percent improved fuel efficiency compared with Tier 3, depending on duty cycle. Machine productivity is boosted beyond that of Tier 3 applications, with faster engine response and significantly higher torque rise. Cleaner and quieter operation is a further noticeable benefit.
“We are very excited to see the arrival of the 11.9-liter and 15-liter QSX engines for Tier 4, as they represent the leading edge of Cummins technical development and will outclass every other engine in their power range,” said Hugh Foden, Executive Director, Cummins Off-Highway Business. “The QSX engines are the culmination of a heavy-duty engine development program with an investment by Cummins of almost $100 million. With the on-highway ISX version of the engine already on the road in North America, this means that the QSX engines will enter the off-highway market with proven performance.
“Equipped with next-generation systems such as XPI fuel injection and VGT Turbochargers, the QSX engines are ready to move forward to meet Tier 4 Final near-zero emissions in 2014 with minimal change,” added Foden.
The Tier 4 QSX15 takes the legendary strength of the Tier 3 base engine and evolves to meet Tier 4 with substantially upgraded combustion, air-handling and fuel injection capability. Power output of the 15-liter engine extends from 400 hp to 600 hp (298-447 kW) with a huge peak torque of 2050 lb-ft (2779 N•m).
The QSX11.9 is a clean-sheet design for Tier 4, sharing technology with the larger QSX15 engine. The 11.9-liter displacement provides a compact solution for 300- to 500-hp (224-373 kW) applications, with an impressive peak torque of 1600 lb-ft (2169 N•m).
Equally significant as the high peak torque is a remarkable torque rise of up to 50 percent, available from both QSX11.9 and QSX15 engine ratings. This enables the engine to more quickly take full advantage of the available torque just as rpm speed falls due to tougher working conditions. The Tier 4 QSX engines also provide installation and operational flexibility for different types of equipment, with power ratings available at 1800 rpm or 2100 rpm engine speeds.
Xtra-High Pressure (XPI) Fuel Injection
Cummins Xtra-High Pressure Injection is the most capable common-rail fuel system ever utilized on a heavy-duty engine. The XPI is able to inject a precise quantity of fuel at extra-high pressure with multiple injection events per cycle. Even for the most demanding equipment duty cycles, the XPI system enables faster, smoother power delivery with lower fuel consumption. The XPI is complemented by the Cummins VGT Turbocharger which is able to continuously vary airflow boost and manage the Exhaust Gas Recirculation (EGR). Electric actuation allows infinite adjustment to provide an exact amount of boost across the rpm range. The unique sliding-nozzle design has fewer moving parts, providing high reliability.
Tier 4 engine management is significantly upgraded with the latest Cummins CM2250 Electronic Control Module (ECM) providing three times faster processing power and double the memory capability compared with the Tier 3 module. This advanced capability also allows a seamless electronic interface to other systems on the equipment.
Cummins Particulate Filter
The Cummins Particulate Filter exhaust aftertreatment replaces the exhaust muffler while providing equivalent sound reduction and is structurally strengthened to withstand severe off-highway shock loads and vibration. Introduced to meet EPA 2007 on-highway emissions, the Cummins Particulate Filter is a proven system with over 450,000 manufactured by Cummins Emission Solutions.
Field tests have demonstrated that Tier 4 equipment powered with a QSX11.9 or QSX15 engine will operate at high enough engine load factors for the Cummins Particulate Filter to clean PM emissions by simple passive regeneration almost every time.
Active regeneration, which is initiated by the injection of a small amount of fuel, typically occurs less than 1 percent of the equipment operating time. The regeneration process takes place automatically and does not impact machine performance or operation.
Direct Flow Air Cleaner
The QSX11.9 and QSX15 engines are integrated with the new Direct Flow air cleaner from Cummins Filtration, specifically developed to provide more performance in less space for Tier 4 applications. Increased dust-holding capacity enables the Direct Flow technology to reduce air cleaner installation space claim compared with conventional cylindrical air cleaners, while achieving equal or better filtration performance. This is achieved by the innovative “V-Block” rectangular configuration of the Direct Flow, which optimizes space normally wasted in the inner diameter of round air filter elements. The Direct Flow housing features an integral sensor for monitoring temperature and pressure to ensure that optimum airflow is delivered to the engine during all operating conditions.
The housing is also available with an optional precleaner cover that is able to remove up to 95 percent of particles before they reach the filter, offering significant benefits for high-dust environments. With enhanced filtration efficiency, Direct Flow offers the opportunity to extend filter service intervals and reduce operating costs.
The engine filtration capability on the QSX engines is also enhanced with a highly efficient coalescing filter to eliminate crankcase blowby gas emissions, as required by the Tier 4 regulations. The filter returns the oil to the crankcase and provides the added benefit of removing oil mist and tiny oil droplets, ensuring that the engine and powertrain remain clean.